6.6-stable review patch. If anyone has any objections, please let me know.
------------------
From: Yuntao Wang <ytcoode@xxxxxxxxx>
commit 932d8476399f622aa0767a4a0a9e78e5341dc0e1 upstream.
Commit 4205e4786d0b ("cpu/hotplug: Provide dynamic range for prepare
stage") added a dynamic range for the prepare states, but did not handle
the assignment of the dynstate variable in __cpuhp_setup_state_cpuslocked().
This causes the corresponding startup callback not to be invoked when
calling __cpuhp_setup_state_cpuslocked() with the CPUHP_BP_PREPARE_DYN
parameter, even though it should be.
Currently, the users of __cpuhp_setup_state_cpuslocked(), for one reason or
another, have not triggered this bug.
Fixes: 4205e4786d0b ("cpu/hotplug: Provide dynamic range for prepare stage")
Signed-off-by: Yuntao Wang <ytcoode@xxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20240515134554.427071-1-ytcoode@xxxxxxxxx
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cpu.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -2495,7 +2495,7 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_inst
* The caller needs to hold cpus read locked while calling this function.
* Return:
* On success:
- * Positive state number if @state is CPUHP_AP_ONLINE_DYN;
+ * Positive state number if @state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN;
* 0 for all other states
* On failure: proper (negative) error code
*/
@@ -2518,7 +2518,7 @@ int __cpuhp_setup_state_cpuslocked(enum
ret = cpuhp_store_callbacks(state, name, startup, teardown,
multi_instance);
- dynstate = state == CPUHP_AP_ONLINE_DYN;
+ dynstate = state == CPUHP_AP_ONLINE_DYN || state == CPUHP_BP_PREPARE_DYN;
if (ret > 0 && dynstate) {
state = ret;
ret = 0;
@@ -2549,8 +2549,8 @@ int __cpuhp_setup_state_cpuslocked(enum
out:
mutex_unlock(&cpuhp_state_mutex);
/*
- * If the requested state is CPUHP_AP_ONLINE_DYN, return the
- * dynamically allocated state in case of success.
+ * If the requested state is CPUHP_AP_ONLINE_DYN or CPUHP_BP_PREPARE_DYN,
+ * return the dynamically allocated state in case of success.
*/
if (!ret && dynstate)
return state;
